When I was breastfeeding my children, their pediatrician was thrilled that I was privileged enough to be able to, but adamant that my children receive adequate amounts of vitamin D through infant drops, as she said breast milk didn't enough for them to thrive. I bought them right away and started dousing my nipples in the banana-flavored vitamins before their last feeding of the day. I was very conscious of the dosage because I knew there were risks of not getting enough vitamin D. However, I wonder if the reverse is true. Can babies get too much vitamin D? Would the risk only be from the drops, or could the sun also pose a threat?
The condition of too much vitamin D, according to The Mayo Clinic, is also called hypervitaminosis D, which "is a rare but potentially serious condition that occurs when you have excessive amounts of vitamin D in your body." There are real risks of vitamin D toxicity. Things like nausea and vomiting, muscle aches, confusion, and even seizures or death can occur from having a megadose of vitamin D in your baby's body. However, it's pretty rare, and according to the Food and Drug Administration (FDA), it's preventable.
The FDA warns that the overdose occurs when too much is administered orally. Linda M. Katz, M.D., M.P.H., interim chief medical officer in FDA's Center for Food Safety and Applied Nutrition, noted that "Parents and caregivers should only use the dropper that comes with the vitamin D supplement purchased" to avoid giving their children too much of the potentially dangerous supplement.
Can babies get too much vitamin D from other sources, like the foods they eat or the sun? According to Katherine Zeratsky, R.D., L.D. for The Mayo Clinic, the answer is no. She wrote, "Vitamin D toxicity is usually caused by megadoses of vitamin D supplements — not by diet or sun exposure. That's because your body regulates the amount of vitamin D produced by sun exposure, and even fortified foods don't contain large amounts of vitamin D."
The way vitamin D is synthesized in your body is actually incredibly cool. According to Harvard University, the sunlight hits your skin, and that triggers a chemical transformation that results in the creation of D3. Unfortunately, in the Northern Hemisphere, there's a narrow window for when this can happen, and because you also need sunblock to prevent cancer, it's hard to get without a supplement — especially for babies. If you do get to see the sun, then the D3 is transported to the liver and then your kidneys where it becomes actual, bioavailable, vitamin D.
As for getting too much vitamin D from nutrition — it's in almost no foods but bones and egg yolk, according to Harvard. True, some foods are D-fortified, but you'd have to eat an astounding amount of cereal drowning in whole milk to get the amount that's in one dropper of supplements.
Nope, the real risk remains in user error — parents simply giving too much to their little ones. The FDA warned that parents should "Ensure that your infant does not receive more than 400 international units (IUs) of vitamin D a day." The best way to make sure you're giving the right dose is to only do it once (even if baby spits up) and use the dropper provided, noted the FDA.
Dr. Bruce Hollis, an MD and scientific researcher had another idea. He suggested in a 2015 study from the American Academy of Pediatrics that breastfeeding mothers instead supplement themselves with 6400 IU vitamin D per day, as opposed to giving your baby anything. His study showed that this is a safe and reliable alternative, and lacked the dangers inherent in dosing your baby.
Whatever you choose to do for your baby, make sure to do it carefully because the risks are real. Anytime you give your child vitamins or medication, do so under strict doctor's supervision.
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